使用OpenSSL生成RSA公钥/私钥？

Question

The main problem is that I'm quite new to C, and the OpenSSL documentation is not clear enough for me, I've tried using Reading and writing rsa keys to a pem file in C , but I don't quite understand it. For example, how does the create_rsa_key() function creates both the private and the public? And where does pCipher come from? And what's the point of the pcszPassphrase ?

I'll explain as if it was some sort of pseudocode, this is what I want to do, and the parts in bold are those I don't know how to do it:

• generate private key and public key as buffers in hex (client)
• send the public key to the other endpoint safely (client)
• encrypt some data with a random 256 bit password using AES256 CBC (server)
• encrypt the password using the public key (server)
• send the encrypted data to the client (server)
• decrypt the encrypted 256 bit password using the private key (client)
• decrypt the file

Basically I know how to handle AES encryption/decryption and the communication protocol, they're already implemented anyway, my issue is RSA, and I need hex format not base64 or pem as I'm working with sockets and sending and storing as binary data.

Answer 1

As discussed on IRC, the answer to the create_rsa_key question is addressed by https://stackoverflow.com/a/29589818/37923 - it's not meant to work that way.

pcszPassphrase is meant to be the password/phrase to protect the private key. It would be provided by the user, but isn't a requirement.